Effectiveness comparison between cervical plate internal fixation and Zero profile interboby fixation system for the treatment of cervical spondylotic myelopathy

Abstract

Objective Compare the clinical efficacy between anterior cervical decompressions, internal fixation with steel plate and zero profile interbody fusion system(Zero-P) in the treatment of cervical spondylotic myelopathy. Methods From October 2010 to May 2013, a total of 47 patients with cervical myelopathy were included in prospective randomized controlled study. All patients were randomly divided into two groups, respectively using plate fixation(screw plate system group, 26 cases) and Zero-P(Zero-P group, 21 cases). Compared operation time, intraoperative blood loss, postoperation flow and the incidence of postoperative discomfort swallowing. Evaluated the Japanese Orthopaedic Association(JOA) score of nerve function and calculated improvement rate; measured cervical Cobb Angle on X-ray film, observed abnormal activity of surgical clearance, evaluated degree of bone graft fusion and related internal fixation complications. Results The average operation time of screw plate system group was 71.2±26.8 min, which was 53.4±28.6 min in Zero-P group, significant difference was found in two groups. The average bleeding volume was 78.1±46.7 ml, and average volume of postoperation drainage was 63.3±37.7 ml in screw plate system group; the average bleeding volume was 77.5±50.4 ml, and the average volume of postoperation drainage was 60.7±28.6 ml in Zero-P group, no significant difference was found. 5 cases in screw plate system group remained swallowing discomfort 3 weeks after operation, but non in Zero-P group. Followed-up lasted for 24-42 months, an average of 23±2.16 months, nerve function were significantly improved at the end of the follow-up of both two groups, the JOA score of screw plate system group was 14.28±2.96, the improvement rate was 68.91%±7.9%, and Zero-P group was 14.32±2.87, the improvement rate was 69.79%±11.2%, there were no significant difference; curvature of cervical vertebrae of screw plate system group was 15.2°±5.7° at the end of follow-up; Zero-P group was 18.1°±7.9°, which with significant difference. Bone graft fusion were found in all patients at the end of follow-up, and no abnormal activities and fixation loosening was found during follow-up period. Conclusion Zero-P compared with traditional fracture-fixation techniques in treating single or double segments of cervical spondylotic myelopathy, can shorten operation time, reduce the incidence of postoperative chronic discomfort swallowing, and maintain in favour of cervical curvature. Key words: Cervical vertebrae; Spinal cord compression; Spinal fusion; Treatment outcome